<template>
  <view class="content">
    <scroll-view scroll-y class="left-aside">
      <view
        v-for="item in level1List"
        :key="item.id"
        class="f-item b-b"
        :class="{ active: item.id === currentId }"
        @click="tabtap(item)"
      >
        {{ item.name }}
      </view>
    </scroll-view>
    <scroll-view
      scroll-with-animation
      scroll-y
      class="right-aside"
      @scroll="asideScroll"
      :scroll-top="tabScrollTop"
    >
      <view
        v-for="item in level2List"
        :key="item.id"
        class="s-list"
        :id="'main-' + item.id"
      >
        <text class="s-item">{{ item.name }}</text>
        <view class="t-list">
          <view
            @click="navToList(item.id, titem.id)"
            v-if="titem.pid === item.id"
            class="t-item"
            v-for="titem in level3List"
            :key="titem.id"
          >
            <image :src="titem.icon"></image>
            <text>{{ titem.name }}</text>
          </view>
        </view>
      </view>
    </scroll-view>
  </view>
</template>

<script>
export default {
  data() {
    return {
      sizeCalcState: false,
      tabScrollTop: 0,
      currentId: 1,
      level1List: [], //1级分类
      level2List: [], //2级分类
      level3List: [], //3级分类
    };
  },
  onLoad() {
    this.loadData();
  },
  methods: {
    async loadData() {
      let res = await this.$http.category.getCategory();
      res.data.forEach((item) => {
        if (!item.pid) {
          this.level1List.push(item); 
        }
        if (item.level == 2) {
          this.level2List.push(item); 
        }
        if (item.level == 3) {
          this.level3List.push(item); 
        }
      });
    },
    //一级分类点击
    tabtap(item) {
      if (!this.sizeCalcState) {
        this.calcSize();
      }

      this.currentId = item.id;
      let index = this.level2List.findIndex((sitem) => sitem.pid === item.id);
      this.tabScrollTop = this.level2List[index].top;
    },
    //右侧栏滚动
    asideScroll(e) {
      if (!this.sizeCalcState) {
        this.calcSize();
      }
      let scrollTop = e.detail.scrollTop;
      let tabs = this.level2List.filter((item) => item.top <= scrollTop).reverse();
      if (tabs.length > 0) {
        this.currentId = tabs[0].pid;
      }
    },
    //计算右侧栏每个tab的高度等信息
    calcSize() {
      let h = 0;
      this.level2List.forEach((item) => {
        let view = uni.createSelectorQuery().select("#main-" + item.id);
        view
          .fields(
            {
              size: true,
            },
            (data) => {
              item.top = h;
              h += data.height;
              item.bottom = h;
            }
          )
          .exec();
      });
      this.sizeCalcState = true;
    },
    navToList(sid, tid) {
      uni.navigateTo({
        url: `/pages/product/list?cate_id1=${this.currentId}&cate_id2=${sid}&cate_id3=${tid}`,
      });
    },
  },
};
</script>

<style lang="scss">
page,
.content {
  height: 100%;
  background-color: #f8f8f8;
}

.content {
  display: flex;
}
.left-aside {
  flex-shrink: 0;
  width: 200upx;
  height: 100%;
  background-color: #fff;
}
.f-item {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100upx;
  font-size: 28upx;
  color: $font-color-base;
  position: relative;
  &.active {
    color: $base-color;
    background: #f8f8f8;
    &:before {
      content: "";
      position: absolute;
      left: 0;
      top: 50%;
      transform: translateY(-50%);
      height: 36upx;
      width: 8upx;
      background-color: $base-color;
      border-radius: 0 4px 4px 0;
      opacity: 0.8;
    }
  }
}

.right-aside {
  flex: 1;
  overflow: hidden;
  padding-left: 20upx;
}
.s-item {
  display: flex;
  align-items: center;
  height: 70upx;
  padding-top: 8upx;
  font-size: 28upx;
  color: $font-color-dark;
}
.t-list {
  display: flex;
  flex-wrap: wrap;
  width: 100%;
  background: #fff;
  padding-top: 12upx;
  &:after {
    content: "";
    flex: 99;
    height: 0;
  }
}
.t-item {
  flex-shrink: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  width: 176upx;
  font-size: 26upx;
  color: #666;
  padding-bottom: 20upx;

  image {
    width: 140upx;
    height: 140upx;
  }
}
</style>
